The history of Pennsylvania began in 1681 when William Penn received a royal charter from King Charles II of England, but human activity in the region precedes that date. Before Pennsylvania was settled by Europeans, the area was home to the Lenape, Susquehannock, Iroquois, Erie, Shawnee and other Native American tribes. Most of these tribes were driven off or reduced to remnants as a result of new diseases such as smallpox that arrived long before any permanent colonists. Pennsylvania was first colonized by Swedish and Dutch settlers in the 17th century, before the English took control of the colony in 1667. In 1681, William Penn established a colony based on religious tolerance; it and its chief city, Philadelphia (the first planned city), were settled by many Quakers. In the mid-eighteenth century, the colony attracted many German and Scots-Irish immigrants

Pennsylvania played a central role in the American Revolution, and Philadelphia served as the nation's capital for much of the 19th century. Starting in the 18th century and continuing into the 20th century, Pennsylvania was the second most populous state in the country, and Philadelphia was the second most populous city in the nation. Pennsylvania also expanded its borders into what is now known as northwestern, northeastern, and southwestern Pennsylvania, and Pittsburgh grew into one of America's largest and most prominent cities. During the Civil War, Pennsylvania played an important role in the Union's victory. After the war, Pennsylvania grew into a Republican stronghold and a major manufacturing and transportation center. After the Great Depression and World War II, Pennsylvania moved towards the service industry and became a swing state.

Pennsylvania's history of human habitation extends to thousands of years before the foundation of the Province of Pennsylvania. Archaeologists generally believe that the first settlement of the Americas occurred at least 15,000 years ago during the last glacial period, though it is unclear when humans first entered the area now known as Pennsylvania. There is an open debate in the archaeological community regrading when the ancestors of Native Americans expanded across the two continents down to the tip of South America, with possibilities ranging between 30,000 and 10,500 years ago.[1] The Meadowcroft Rockshelter contains the earliest known signs of human activity in Pennsylvania, and perhaps all of North America,[2] as it contains the remains of a civilization that existed over 10,000 years ago and possibly pre-dated the Clovis culture.[3][2] By 1000 C.E., in contrast to their nomadic hunter-gathererancestors, the native population of Pennsylvania had developed agricultural techniques and a mixed food economy.[4]

In addition to English Quakers, Pennsylvania attracted several other ethnic and religious groups, many of whom were fleeing persecution and the religious wars. WelshQuakers settled a large tract of land north and west of Philadelphia, in what are now Montgomery, Chester, and Delaware counties. This area became known as the "Welsh Tract", and many cities and towns were named for points in Wales. The colony's reputation of religious freedom and tolerance also attracted significant populations of German, Scots-Irish, Scottish, and French settlers. Many of the settlers worshiped a brand of Christianity disfavored by the government of their homeland; Huguenots, Puritans, Catholics, and Calvinists all migrated to Pennsylvania. Other groups, including Anglicans and Jews, migrated to Pennsylvania, while Pennsylvania also had a significant African-American population by 1730. Additionally, several Native American tribes and settlers of Swedish and Dutch origin continued to live in the region.[3][10]

During the French and Indian War, Pennsylvania settlers experienced raids from Indian allies of the French. The settlers' pleas for military relief were stymied by a power struggle in Philadelphia between Governor Robert Morris and the Pennsylvania Assembly. Morris wanted to send military forces to the frontier, but the Assembly, whose leadership included Benjamin Franklin, refused to grant the funds unless Morris agreed to the taxation of the proprietary lands, the vast tracts still owned by the Penn family and others. The dispute was finally settled, and military relief sent, when the owners of the proprietary lands sent 5,000 pounds to the colonial government, on condition that it was considered a free gift and not a down payment on taxes.[12]

After elections in May 1776 returned old guard Assemblymen to office, the Second Continental Congress encouraged Pennsylvania to call delegates together to discuss a new form of governance. Delegates met in June in Philadelphia, where events (the signing of the Declaration of Independence) soon overtook assemblymen's efforts to control the delegates and the outcome of their discussions. On July 8 attendees elected delegates to write a state constitution. A committee was formed with Benjamin Franklin as chair and George Bryan and James Cannon as prominent members. The convention proclaimed a new constitution on September 28, 1776 and called for new elections.[15]

Elections in 1776 turned the old assemblymen out of power. But the new constitution lacked a governor or upper legislative house to provide checks against popular movements. It also required test oaths, which kept the opposition from taking office. The constitution called for a unicameral legislature or Assembly. Executive authority rested in a Supreme Executive Council whose members were to be appointed by the assembly. In elections during 1776, radicals gained control of the Assembly. By early 1777, they selected an executive council, and Thomas Wharton, Jr. was named as the President of the Council. This constitution was never formally adopted, so government was on an ad-hoc basis until a new constitution could be written fourteen years later.

In 1780, Pennsylvania passed a law that provided for the gradual abolition of slavery, making Pennsylvania the first state to pass an act to abolish slavery (although Vermont had also previously abolished slavery).[16] Children born after that date to slave mothers were considered legally free, but they were bound in indentured servitude to the master of their mother until the age of 28. The last slave was recorded in the state in 1847.

After the United States government granted land to Revolutionary War soldiers for military service, the Pennsylvania General Assembly passed a general land act on April 3, 1792. It authorized the sale and distribution of the large remaining tracts of land east and west of the Allegheny River in hopes of sparking development of the vast territory. The process was an uneven affair, prompting much speculation but little settlement. Most veteran soldiers sold their shares sight unseen under market value, and many investors were ultimately ruined. The East Allegheny district consisted of lands in Potter, McKean, Cameron, Elk, and Jefferson counties, at the time worthless tracts. West Allegheny district was made up of lands in Erie, Crawford, Warren, and Venango counties, relatively good investments at the time.

The Whiskey Rebellion, centered in Western Pennsylvania, was one of the first major challenges to the new federal government under the United States Constitution. From 1791-1794, farmers rebelled against an excise tax on distilled spirits, and prevented federal officials from collecting the tax. In 1794, President George Washington led a militia into Western Pennsylvania to put down the rebellion, although most rebels returned home before the militia arrived.

Pennsylvania had established itself as the largest food producer in the country by the 1720s, and Pennsylvania agriculture experienced a "golden age" from 1790 to 1840. In 1820, agriculture provided 90 percent of the employment in Pennsylvania. Farm equipment manufacturers sprang up across the state as inventors across the world pioneered new equipment and techniques, and Pennsylvanians such as Frederick Watts were a part of this scientific approach to farming. Although Pennsylvania farmers lost some of their political power as other industries emerged in the state, but even in the 2000s agriculture remains one of Pennsylvania's major industries.[21]

In 1834, Governor George Wolf signed the Free Schools Act, which created a system of state-regulated school districts. The state created the Department of Education to oversee these schools. In 1857, the Normal School Act laid the foundation for the creation of normal schools to train teachers.[22]

The Pennsylvania Republican party was led by a series of bosses, including founder Simon Cameron, his son J. Donald Cameron, Matthew Quay, and Boies Penrose.[25] Quay in particular was one of the dominant political figures of his era, as he served as chairman of the Republican National Committee and helped place Theodore Roosevelt on the 1900 Republican ticket.[26] Following Penrose's death in the 1920s, no one boss dominated the state party, but Pennsylvania Republicans continued to be significantly more powerful than the Democrats until the 1950s.[25] Although the party bosses dominated politics, the Republicans also had a reform movement that challenged the power of the bosses.[27] Many Pennsylvanians supported the Progressive movement, including Philander C. Knox, Gifford Pinchot, and John Tener.[28] Several new state agencies were established during this time, including the Department of Welfare and the Department of Labor and Industry.[24] Pennsylvanians twice rejected an amendment to the state constitution that would have granted women the right to vote, but the state was one of the first to ratify the Nineteenth Amendment, which granted women the right to vote nationwide.[24]

Hazleton coal miners in 1900. Coal mining was a major economic activity in Pennsylvania in the 19th and 20th centuries.

The growth of industry eventually provided middle-class incomes to working-class households, after the development of labor unions helped them gain living wages. However, the rise of unions led to a rise of union busting, with several private police forces springing up.[29] Pennsylvania was the location of the first documented organized strike in North America, and Pennsylvania experienced the Great Railroad Strike of 1877 and the Coal Strike of 1902. Eventually, the eight hour day was adopted, and the "coal and iron police" were banned.[30][24]

During this period, the United States was the destination of millions of immigrants. Previous immigration had mostly come from western and northern Europe, but during this period Pennsylvania experienced heavy immigration from southern and eastern Europe.[24] As many new immigrants were Catholic and Jewish, they changed the demographics of major cities and industrial areas. Pennsylvania and New York received many of the new immigrants, who entered through New York and Philadelphia and worked in the developing industries. Many of these poor immigrants took jobs in factories, steel mills, and coal mines throughout the state, where they were not restricted because of their lack of English. The availability of jobs and public education systems helped integrate the millions of immigrants and their families, who also retained ethnic cultures. Pennsylvania also experienced the Great Migration, in which millions of African Americans migrated from the southern United States to other locations in the United States. By 1940, African Americans made up almost five percent of the state's population.[24]

Even before the Civil War, Pennsylvania had emerged as a center of scientific discovery, and the state, led by its two major urban centers, continued to be a major place of innovation. The state continued to innovate, as Pennsylvanians invented the first iron and steel t-rails, iron bridges, air brakes, switching signals, and drawn metal wires. Pennsylvanians also contributed to advances in aluminum production, radio, television, airplanes, and farm machinery. During this period, Pittsburgh emerged as an important center of industry and technological innovation, and George Westinghouse became one of the preeminent inventors of the United States.[31] Philadelphia became one of the leading medical science centers in the nation, although it no longer rivaled New York City as a financial capital.[24]Frederick Winslow Taylor pioneered the field of scientific management, becoming America's first "efficiency engineer."[24] By 1910, Chicago had passed Philadelphia as the second most populous city in the United States, while Pittsburgh rose to the eighth spot after annexing Allegheny.

As with much of the rest of the country, Democrats were much more successful in Pennsylvania during the Fifth Party System than they were in the previous two party systems. The Great Depression finally broke the lock on Republican power in the state, as Democrat Franklin Roosevelt won Pennsylvania's electoral votes in all three of his re-election campaigns. Roosevelt was the first Democrat to win the state's electoral votes since James Buchanan in 1856. In 1934, Pennsylvania elected Joseph F. Guffey to the Senate and George Earle III as governor; both individuals were the first Democrats elected to either office in the 20th century. Earle, with the help of a Democratic legislature, passed the "Little New Deal" in Pennsylvania, which included several reforms based on the New Deal and relaxed Pennsylvania's strict Blue laws.[32][33] However, Republicans regained power in the state in the 1938 elections, and Democrats would not win another gubernatorial election until George M. Leader's successful candidacy in 1954.[25]

Earle signed the Pennsylvania State Authority Act in 1936, which would purchase land from the state and add improvements to that land using state loans and grants. The state expected to receive federal grants and loans to fund the project under the administration of President Franklin D. Roosevelt and his New Deal. The Pennsylvania Supreme Court, in Kelly v Earle, found the Act violated the state constitution.[34] This prevented the state from receiving federal funds for Works Progress Administration projects and making it difficult to lower the extremely high unemployment rate. Pennsylvania, with its large industrial labor force, suffered heavily during the Great Depression.[24]

The Republican lock on Pennsylvania was permanently broken in the era after World War II, and Pennsylvania became a somewhat less powerful state in terms of electoral votes and number of House seats. Pennsylvania adopted its fifth and current constitution in 1968; the new constitution established a unified judicial system and allows governors and the other statewide elected officials to serve two consecutive terms.[36] Between 1954 and 2012, each party consistently won two straight gubernatorial elections before ceding control to the other party. In presidential elections, the Republican Party won Pennsylvania in seven of the eleven elections between 1948 and 1988, but Democrats have won the state in every presidential election from 1992 to 2012. When Democratic presidential nominee Hubert Humphrey won Pennsylvania's electoral votes in 1968, he became the first non-Republican since 1824 to win Pennsylvania's votes without winning the presidential election. After having the second most electoral votes since the 18th century, Pennsylvania was eclipsed in electoral votes by California in 1964. Texas and Florida also now have more electoral votes, while New York also has more electoral votes and Illinois has the same number of electoral votes (and a slightly larger population). As of 2014, Pennsylvania is generally considered to be an important swing state in both presidential and congressional elections, and Pennsylvania has a Cook PVI of D+1. Since the 1990s, Republicans have usually controlled both houses of the legislature, while candidates from both parties have been elected to the statewide offices of governor, lieutenant governor, attorney general, treasurer, and auditor general. Democrats generally win the cities and Republicans win the rural areas, with the suburbs voting for both parties and often acting as the key swing areas.[37]

The state was hard-hit by the decline and restructuring of the steel industry and other heavy U.S. industries during the late 20th century. With job losses came heavy population losses, especially in Philadelphia and Pittsburgh. With the end of mining and the downturn of manufacturing, the state has turned to service industries. Pittsburgh's condensation of universities has enabled it to be a leader in technology and healthcare. Similarly, Philadelphia has a concentration of university expertise. Healthcare, retail, transportation, and tourism are some of the state's growing industries of the postindustrial era. As in the rest of the nation, most residential population growth has occurred in suburban rather than central city areas, although both major cities have had significant revitalization in their downtown areas.[38] Pittsburgh lost its place among the top ten most populous cities in the United States after the 1940s, while Philadelphia is now the fifth largest city after New York, Los Angeles, Chicago, and Houston. Philadelphia anchors the sixth-largestmetropolitan area in the country, while Pittsburgh is the center of the twenty-second largest metro area in the country. The growth of the Lehigh Valley has made it one of the seventy most populous metro areas in the country,[39] while Pennsylvania also has six other metro areas among the top 200 most populous American metro areas. Philadelphia forms part of the Northeast megalopolis and is associated with the Northeastern United States, while Pittsburgh is part of the Great Lakes Megalopolis and is often associated with the Midwestern United States and the Rust Belt.